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1.
Metallic nanostructures with hollow interiors or tailored porosity represent a special class of attractive materials with
intriguing chemicophysical properties. This paper presents the fabrication of a new type of metallic nanoporous nanotube structure
based on a facile and effective combination of nanocrystal growth and surface modification. By controlling the individual
steps involved in this process, such as nanowire growth, surface modification, thermal diffusion, and dealloying, one-dimensional
(1-D) metallic nanostructures can be prepared with tailored structural features and pre-designed functionalities. These tubular
and porous nanostructures show distinct optical properties, such as tunable absorption in the near-infrared region, and enhanced
capability for electrochemiluminescence signal amplification, which make them particularly desirable as novel 1-D nanocarriers
for biomedical, drug delivery and sensing applications.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
2.
Christine H. Moran Sean M. Wainerdi Tonya K. Cherukuri Carter Kittrell Benjamin J. Wiley Nolan W. Nicholas Steven A. Curley John S. Kanzius Paul Cherukuri 《Nano Research》2009,2(5):400-405
Capacitively coupled shortwave radiofrequency fields (13.56 MHz) resistively heat low concentrations (∼1 ppm) of gold nanoparticles
with a thermal power dissipation of ∼380 kW/g of gold. Smaller diameter gold nanoparticles (< 50 nm) heat at nearly twice
the rate of larger diameter gold nanoparticles (≥50 nm), which is attributed to the higher resistivity of smaller gold nanostructures.
A Joule heating model has been developed to explain this phenomenon and provides critical insights into the rational design
and engineering of nanoscale materials for noninvasive thermal therapy of cancer.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
These two authors made an equal contribution to the work. 相似文献
3.
Bimetallic PtAu heteronanostructures have been synthesized from Pt-on-Au nanoparticles, which were made from platinum acetylacetonate
and gold nanoparticles. Using the Pt-on-Au nanoparticles as precursors, Ptsurface rich PtAu bimetallic heteronanostructures
can be produced through controlled thermal treatments, as confirmed by field emission high-resolution transmission electron
microscopy (HR-TEM) and elemental mapping using a high-angle annular dark-field scanning transmission electron microscope
(HAADF-STEM). Oxidation of formic acid was used as a model reaction to demonstrate the effects of varying composition and
surface structure on the catalytic performance of PtAu bimetallic nanostructures. Cyclic voltammetry (CV) showed that these
carbon-supported PtAu heteronanostructures were much more active than platinum in catalyzing the oxidation of formic acid,
judging by the mass current density. The results showed that postsynthesis modification can be a very useful approach to the
control of composition distributions in alloy nanostructures.
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4.
We have studied the morphology evolution of holed nanostructures formed by aluminum droplet epitaxy on a GaAs surface. Unique
outer rings with concentric inner holed rings were observed. Further, an empirical equation to describe the size distribution
of the outer rings in the holed nanostructures has been established. The contour line generated by the equation provides physical
insights into quantum ring formation by droplets of group III materials on III–V substrates.
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5.
We report synthesis windows for growth of millimeter-long ZnTe nanoribbons and ZnSe nanowires using vapor transport. By tuning
the local conditions at the growth substrate, high aspect ratio nanostructures can be synthesized. A Cu-ion immersion doping
method was applied, producing strongly p-type conduction in ZnTe and ionic conduction in ZnSe. These extreme aspect ratio
wide-bandgap semiconductors have great potential for high density nanostructured optoelectronic circuits.
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6.
Chemistry gives us the ability to manipulate atoms and molecules into nanometer and micrometer scale building blocks, while
the science of crystallography is concerned with the spatial arrangement of atoms, ions, and molecules and thus the morphology
and structures of materials. Complex three-dimensional ZnS nanostructures have been fabricated via step-by-step crystallographically-controlled
chemical processes. Tricrystals of ZnS whiskers were prepared via a controlled thermal evaporation process, and then the tricrystals
were thermally treated in an atmosphere formed by evaporating B-N-O precursors into N2/NH3 to afford BN-coated arrays of nanobranches. The ZnS nanobranches grew epitaxially on the ternary facets and extended in three
[0001] directions forming ordered nanostructures. Meanwhile, the protecting insulating sheath of BN formed on the ZnS nanostructures
confined the growth of the nanospines and enhanced their stability. The method may be extended to fabricate other semiconductor
nanomaterials with novel structures.
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7.
Using magnetic nanoparticles to enhance gene transfection, a recently developed technique termed magnetofection, has been
shown to be a powerful technology in gene delivery. The most widely used magnetic nanoparticles in this area are those coated
with polyethyleneimine, which is a well known nonviral transfection agent. In this article, we report methods to control the
aggregate size of polyethyleneimine-coated magnetite particles. These particles were then used to enhance transfection of
green fluorescent protein (GFP) into NIH 3T3 cells in vitro. We find that the aggregate size of the particles has a great effect on their performance in magnetofection, with less aggregated
magnetic particles being more effective in enhancing the gene transfection.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
8.
Synthesis of high magnetic moment CoFe nanoparticles via interfacial diffusion in core/shell structured Co/Fe nanoparticles 总被引:1,自引:0,他引:1
We report the synthesis of high magnetic moment CoFe nanoparticles via the diffusion of Co and Fe in core/shell structured
Co/Fe nanoparticles. In an organic solution, Co nanoparticles were coated with a layer of Fe to form a Co/Fe core/shell structure.
Further raising the solution temperature led to inter-diffusion of Co and Fe and formation of CoFe alloy nanoparticles. These
nanoparticles have high saturation magnetization of up to 192 emu/g CoFe and can be further stabilized by thermal annealing
at 600 °C.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
These two authors made an equal contribution to the work. 相似文献
9.
The strong hydrogen bonding ability of 2-pyridones were exploited to build nanotrains on surfaces. Carborane wheels on axles
difunctionalized with 2-pyridone hydrogen bonding units were synthesized and displayed spontaneous formation of linear nanotrains
by self-assembly on SiO2 or mica surfaces. Imaging using atomic force microscopy confirmed linear formations with lengths up to 5 μm and heights within
the range of the molecular height of the carborance-tipped axles.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
This article is published with open access at Springerlink.com 相似文献
10.
Two simple methods have been demonstrated to obtain large area, single crystalline lamellae of copper-7,7,8,8-tetracyanoquinodimethane
(CuTCNQ). The formation of the lamellae was a result of fine tuning of the processes during the synthesis processes of CuTCNQ
phase II. This facile synthesis of large area single crystalline lamellae suggests bright prospects for the study and understanding
of the electrical switching of CuTCNQ by using single crystals of its phase II, and future applications of the material in
memory and switching devices.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
11.
Wei Xu Mingdong Dong Henkjan Gersen Socorro Vázquez-Campos Xavier Bouju Erik Lægsgaard Ivan Stensgaard Mercedes Crego-Calama David N. Reinhoudt Trolle R. Linderoth Flemming Besenbacher 《Nano Research》2009,2(7):535-542
We present an interplay of high-resolution scanning tunneling microscopy imaging and the corresponding theoretical calculations
based on elastic scattering quantum chemistry techniques of the adsorption of a gold-functionalized rosette assembly and its
building blocks on a Au(111) surface with the goal of exploring how to fabricate functional 3-D molecular nanostructures on
surfaces. The supramolecular rosette assembly stabilized by multiple hydrogen bonds has been sublimed onto the Au(111) surface
under ultra-high vacuum conditions; the resulting surface nanostructures are distinctly different from those formed by the
individual molecular building blocks of the rosette assembly, suggesting that the assembly itself can be transferred intact
to the surface by in situ thermal sublimation. This unanticipated result will open up new perspectives for growth of complex 3-D supramolecular nanostructures
at the vacuum-solid interface.
This article is published with open access at Springerlink.com 相似文献
12.
Juan Yan Mei Hu Di Li Yao He Rui Zhao Xingyu Jiang Shiping Song Lianhui Wang Chunhai Fan 《Nano Research》2008,1(6):490-496
A novel nano- and micro-integrated protein chip (NMIPC) that can detect proteins with ultrahigh sensitivity has been fabricated.
A microfluidic network (μFN) was used to construct the protein chips, which allowed facile patterning of proteins and subsequent
biomolecular recognition. Aqueous phase-synthesized, water-soluble fluorescent CdTe/CdS core-shell quantum dots (aqQDs), having
high quantum yield and high photostability, were used as the signaling probe. Importantly, it was found that aqQDs were compatible
with microfluidic format assays, which afforded highly sensitive protein chips for cancer biomarker assays.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
13.
Current methods of synthesizing single-walled carbon nanotubes (SWNTs) result in racemic mixtures that have impeded the study
of left- and right-handed SWNTs. Here we present a method of isolating different SWNT enantiomers using density gradient ultracentrifugation.
Enantiomer separation is enabled by the chiral surfactant sodium cholate, which discriminates between left- and right-handed
SWNTs and thus induces subtle differences in their buoyant densities. This sorting strategy can be employed for simultaneous
enrichment by handedness and roll-up vector of SWNTs having diameters ranging from 0.7 to 1.5 nm. In addition, circular dichroism
of enantiomer refined samples enables identification of high-energy optical transitions in SWNTs.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
14.
Bhupendra Chudasama Anjana K. Vala Nidhi Andhariya R. V. Upadhyay R. V. Mehta 《Nano Research》2009,2(12):955-965
We describe a simple one-pot thermal decomposition method for the production of a stable colloidal suspension of narrowly
dispersed superparamagnetic Fe3O4-Ag core-shell nanostructures. These biocompatible nanostructures are highly toxic to microorganisms. Antimicrobial activity
studies were carried out on both Gram negative (Escherichia coli and Proteus vulgaris) and Gram positive (Bacillus megaterium and Staphylococcus aureus) bacterial strains. Efforts have been made to understand the underlying molecular mechanism of such antibacterial actions.
The effect of the core-shell nanostructures on Gram negative strains was found to be better than that observed for silver
nanoparticles. The minimum inhibitory concentration (MIC) values of these nanostructures were found to be considerably lower
than those of commercially available antibiotics. We attribute this enhanced antibacterial effect of the nanostructures to
their stability as a colloid in the medium, which modulates the phosphotyrosine profile of the bacterial proteins and arrests
bacterial growth. We also demonstrate that these core-shell nanostructures can be removed from the medium by means of an external
magnetic field which provides a mechanism to prevent uncontrolled waste disposal of these potentially hazardous nanostructures.
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15.
Based on the underlying graphene lattice symmetry and an itinerant magnetism model on a bipartite lattice, we propose a unified
geometric rule for designing graphene-based magnetic nanostructures: spins are parallel (ferromagnetic (FM)) on all zigzag
edges which are at angles of 0° and 120° to each other, and antiparallel (antiferromagnetic (AF)) at angles of 60° and 180°.
The rule is found to be consistent with all the systems that have been studied so far. Applying the rule, we predict several
novel graphene-based magnetic nanostructures: 0-D FM nanodots with the highest possible magnetic moments, 1-D FM nanoribbons,
and 2-D magnetic superlattices.
相似文献
16.
Albert G. Nasibulin Simas Rackauskas Hua Jiang Ying Tian Prasantha Reddy Mudimela Sergey D. Shandakov Larisa I. Nasibulina Sainio Jani Esko I. Kauppinen 《Nano Research》2009,2(5):373-379
We propose a simple method for the efficient and rapid synthesis of one-dimensional hematite (α-Fe2O3) nanostructures based on electrical resistive heating of iron wire under ambient conditions. Typically, 1–5 μm long α-Fe2O3 nanowires were synthesized on a time scale of seconds at temperatures of around 700 ° ⊂. The morphology, structure, and mechanism
of formation of the nanowires were studied by scanning and transmission electron microscopies, energy dispersive X-ray spectroscopy,
X-ray photoelectron spectroscopy, and Raman techniques. A nanowire growth mechanism based on diffusion of iron ions to the
surface through grain boundaries and to the growing wire tip through stacking fault defects and due to surface diffusion is
proposed.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
17.
The performance limits of a multilayer graphene nanoribbon (GNR) field-effect transistor (FET) are assessed and compared with
those of a monolayer GNRFET and a carbon nanotube (CNT) FET. The results show that with a thin high dielectric constant (high-κ) gate insulator and reduced interlayer coupling, a multilayer GNRFET can significantly outperform its CNT counterpart with
a similar gate and bandgap in terms of the ballistic on-current. In the presence of optical phonon scattering, which has a
short mean free path in the graphene-derived nanostructures, the advantage of the multilayer GNRFET is even more significant.
Simulation results indicate that multilayer GNRs with incommensurate non-AB stacking and weak interlayer coupling are the
best candidates for high-performance GNRFETs.
相似文献
18.
We report a theoretical investigation of self-assembled nanostructures of polymer-grafted nanoparticles in a block copolymer
and explore underlying physical mechanisms by employing the self-consistent field method. By varying the particle concentration
or the chain length and density of the grafted polymer, one can not only create various ordered morphologies (e.g., lamellar
or hexagonally packed patterns) but also control the positions of nanoparticles either at the copolymer interfaces or in the
center of one-block domains. The nanostructural transitions we here report are mainly attributed to the competition between
entropy and enthalpy.
相似文献
19.
Hongwang Zhang Savas Delikanli Yueling Qin Shuli He Mark Swihart Hao Zeng 《Nano Research》2008,1(4):314-320
Semiconductor nanocrystals (dots, rods, wires, etc.) exhibit a wide range of electrical and optical properties that differ
from those of the corresponding bulk materials. These properties depend on both nanocrystal size and shape. Compared with
nanodots, nanorods have an additional degree of freedom, the length or aspect ratio, and reduced symmetry, which leads to
anisotropic properties. In this paper, we report the Au nanoparticlecatalyzed colloidal synthesis of monodisperse CdS nanorods.
Based on systematic high resolution transmission electron microscopy studies, we propose a growth mechanism for these nanorods.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
This article is published with open access at Springerlink.com 相似文献
20.
Bi<Subscript>2</Subscript>S<Subscript>3</Subscript> nanostructures: A new photocatalyst 总被引:2,自引:0,他引:2
Uniform colloidal Bi2S3 nanodots and nanorods with different sizes have been prepared in a controllable manner via a hot injection method. X-ray
diffraction (XRD) results show that the resulting nanocrystals have an orthorhombic structure. Both the diameter and length
of the nanorods increase with increasing concentration of the precursors. All of the prepared Bi2S3 nanostructures show high efficiency in the photodegradation of rhodamine B, especially in the case of small sized nanodots—which
is possibly due to their high surface area. The dynamics of the photocatalysis is also discussed.
相似文献